Area Forecast Discussion
Issued by NWS Hastings, NE

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068
FXUS63 KGID 151743
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
1243 PM CDT FRI MAY 15 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 425 AM CDT FRI MAY 15 2015

FOCUS IS ON TSTMS AND THE POTENTIAL FOR SEVERE WEATHER.

THE PATTERN ALOFT FEATURED SOUTHWEST FLOW ACROSS THE CENTRAL PLAINS
AHEAD OF A LOW PRESSURE SYSTEM IN CALIFORNIA. AT THE SURFACE...LOW
PRESSURE WAS DEEPENING IN EASTERN COLORADO AND SOUTHERLY LLVL WINDS
WERE DRAWING MOISTURE NORTHWARD FROM THE SOUTHERN PLAINS.

CURRENTLY...ISENTROPIC LIFT/WAA AHEAD OF THE WESTERN TROUGH AND ON
THE NOSE OF A 40KT LLVL JET...HAVE INITIATED TSTMS ACROSS PORTIONS
OF NW KANSAS EARLY THIS MORNING. THE STORMS HAVE BEEN OF THE PULSE
VARIETY WITH INSTABILITY BETWEEN 500 AND 1000 J/KG WITH EFFECTIVE
SHEAR OF 25KTS OR LESS. CANNOT RULE OUT A STRONG TO SEVERE STORM
CAPABLE OF PRODUCING 40 TO 50 MPH WINDS AND NICKEL TO QUARTER SIZE
HAIL EARLY THIS MORNING. THE SCATTERED CONVECTION IS EXPECTED TO
LIFT NORTH/NORTHEAST TODAY IN WAA ASSOCIATED WITH A LEAD SHORTWAVE
TROUGH CROSSING OUR REGION.

HEADING INTO THE DAY TODAY THE SFC LOW WILL DEEPEN IN EASTERN CO
WITH ANOTHER SFC LOW DEVELOPING FARTHER NORTH IN WY. A WARM FRONTAL
BOUNDARY WILL LIFT NORTHWARD...WITH SHOWERS AND THUNDERSTORMS
EXPECTED TO CONTINUE ALONG AND NORTH OF THE FRONTAL BOUNDARY. IN
THEORY THERE SHOULD BE A BREAK IN ROUNDS OF CONVECTION TODAY HOWEVER
SOME MODELS SUGGEST STORMS WILL BE AROUND INTERMITTENTLY THRU
TONIGHT. IN BETTER MOISTURE/INSTABILITY AND SHEAR THIS AFTN/EVENING
CONDITIONS REMAIN FAVORABLE FOR SEVERE WEATHER WITH LARGE
HAIL/DAMAGING WINDS THE PRIMARY HAZARDS...BUT CANNOT RULE OUT A
TORNADO IN THE VCNTY OF BOUNDARIES.

THE WESTERN UPPER LOW REACHES THE CENTRAL ROCKIES TONIGHT AND THE
SURFACE LOW/TROUGH REMAIN ORIENTED ALONG THE HIGH PLAINS REGION. AN
INTENSE LLVL JET STRENGTHENS TO 50KTS AND AGAIN WAA AND DYNAMICS
AHEAD OF THE UPPER LOW WILL PROVIDE SUFFICIENT FORCING FOR ELEVATED
OVERNIGHT CONVECTION. INSTABILITY IS PROGGED JUST OVER 1000 J/KG
WITH SHEAR AVERAGES 30KTS OR SO AND AGAIN CANNOT RULE OUT A STRONG
TO SEVERE STORM FOR TONIGHT.  ALL IN ALL...THE WEATHER WILL BE
INTERMITTENTLY ACTIVE WITH THE POTENTIAL FOR SEVERE WEATHER THROUGH
THE NEXT 24 HOURS.

.LONG TERM...(SATURDAY DAYTIME THROUGH THURSDAY)
ISSUED AT 425 AM CDT FRI MAY 15 2015

CERTAINLY THE NUMBER ONE ISSUE DURING THIS 6-DAY PERIOD IS THE
ENHANCED RISK OF SEVERE THUNDERSTORMS PRIMARILY CENTERED ON
SATURDAY AFTERNOON/EVENING. ALTHOUGH AT LEAST A FEW SEVERE
THUNDERSTORMS ARE ALMOST A FOREGONE CONCLUSION WITHIN THE CWA
DURING THIS TIME FRAME (POTENTIALLY SEVERAL)...THERE IS STILL
PLENTY OF UNCERTAINTY REGARDING THE DETAILS OF TIMING...COVERAGE
AND WHETHER OR NOT THE TORNADO THREAT COULD BE SOMEWHAT "HIGHER
END"...OR FAIRLY LIMITED...AND MUCH OF THIS WILL PROBABLY DEPEND
ON STORM MODE. OVERALL FEELING AT THIS POINT IS THAT SOMEWHAT
"MESSY" STORM MODE SHOULD LIMIT THE MAGNITUDE OF THE TORNADO
THREAT SOMEWHAT...BUT WITH SUCH STRONG DYNAMICS AT PLAY AT LEAST A
FEW TORNADIC STORMS MAY BE DIFFICULT TO AVOID. OF COURSE...AS
EVIDENCED BY HOW THINGS TURNED OUT WITH LAST WEEKEND`S
SYSTEM...EVEN AT THIS DAY 2 RANGE THINGS ARE NOT SET IN
STONE...BUT FOLKS NEED TO REMAIN "WEATHER AWARE" SATURDAY INTO
SATURDAY NIGHT FOR SURE. BASED ON THE LATEST INSTABILITY PROGS
FROM MODELS SUCH AS THE 06Z NAM...LARGELY AGREE WITH SPC THAT THE
OVERALL HIGHEST SEVERE PROBABILITIES ARE WARRANTED WITHIN THE
SOUTHWEST HALF OF THE CWA...WITH SLIGHTLY LESSER POTENTIAL
NORTHEAST.

BEYOND SATURDAY NIGHT...THERE ARE CURRENTLY NO OBVIOUS CONCERNS
FOR "HIGH IMPACT" WEATHER THROUGH THE REMAINDER OF THE PERIOD...AS
IF NOTHING ELSE...THE ISOLATED THUNDERSTORM MENTION CURRENTLY IN
PLACE FOR TUESDAY-WEDNESDAY IS PROBABLY ON FAIRLY SHAKY GROUND AS
INSTABILITY STILL LOOKS QUITE LIMITED IF NOT ALMOST NON-EXISTENT.
TEMPERATURE-WISE...THE MAIN STORY FOR THE MAJORITY OF NEXT WEEK
REMAINS A SEASONABLY COOL PATTERN...WITH HIGHS ACROSS MOST OF THE
AREA FROM MONDAY-THURSDAY CURRENTLY AIMED WELL DOWN INTO THE
60S...AND MAYBE EVEN ONLY 50S FOR PARTS OF THE CWA ON DAYS SUCH AS
WEDNESDAY. OVERNIGHT LOWS ARE AIMED INTO THE 40S DURING THIS SAME
TIME FRAME. ALTHOUGH IT SEEMS HARD TO BELIEVE THIS LATE INTO
MAY...SOME OF THE RAW 00Z MODEL GUIDANCE SUCH AS FROM THE MEX/ECE
SUGGEST THAT NORTHERN/WESTERN PARTS OF THE CWA COULD EVEN FLIRT
WITH UPPER-END FROST-WORTHY TEMPERATURES ESPECIALLY AROUND
TUESDAY MORNING...BUT AT LEAST FOR NOW THE OFFICIAL FORECAST KEEPS
LOWS SEVERAL DEGREES ABOVE THIS.

WILL NOT BE DIVING INTO TOO MANY METEOROLOGICAL DETAILS...BUT
HERE ARE SOME DAY-BY-DAY GENERALITIES/EXPECTATIONS IN 12-24 HOUR
BLOCKS...

SATURDAY DAYTIME/NIGHT: IN THE LARGE SCALE PICTURE...VARIOUS
DETERMINISTIC MODELS ARE IN GOOD AGREEMENT THAT THE LEADING EDGES
OF THE PRIMARY MID-UPPER LEVEL LOW OVER COLORADO WILL START
KICKING OUT INTO THE CENTRAL PLAINS IN SLIGHTLY NEGATIVELY TILTED
FASHION AS THE DAY WEARS ON...AS A STRONG 80-90+ KT SOUTHERLY
UPPER LEVEL JET STREAK SHIFTS INTO THE LOCAL AREA...PROVIDING
PLENTY OF LIFT/DIFFLUENCE. LEANING SOMEWHAT ON THE SIMULATED
REFLECTIVITY SOLUTIONS OF MODELS SUCH AS THE 4KM WRF-NMM/ARW AND
4KM NAM...EXPECT THERE COULD BE TWO DISTINCT ROUNDS OF STORMS
DURING THE DAY...WITH A POTENTIALLY MULTI-HOUR LULL IN BETWEEN
DURING WHICH NOT A WHOLE LOT MAY BE GOING ON. IN GENERAL...MAINLY
THE SOUTHEAST HALF OF THE CWA COULD SEE AN AREA OF STORMS LIFTING
NORTHEAST ACROSS THE AREA DURING THE MORNING...ESSENTIALLY A
CONTINUATION OF ACTIVITY THAT MIGHT GET UNDERWAY LATE TONIGHT.
THIS EARLY ACTIVITY COULD BE MARGINALLY SEVERE...BUT WILL LIKELY
NOT BE THE "MAIN EVENT". FOLLOWING A MID-DAY LULL...THE PRIMARY
AREA OF SEVERE STORMS IS EXPECTED TO INITIATE SLIGHTLY TO THE
WEST/SOUTHWEST OF THE CWA MID-LATE AFTERNOON ALONG THE MAIN
SURFACE DRYLINE...AND QUICKLY TRACK NORTH-NORTHEAST INTO THE CWA
IN AN ENVIRONMENT CHARACTERIZED BY HEALTHY DEEP LAYER SHEAR OF AT
LEAST 40-50KT. ALTHOUGH ALL MODES OF SEVERE WEATHER APPEAR
POSSIBLE...THESE HIGHER RES MODELS ARE LARGELY SUPPORTIVE OF A
SOMEWHAT "MESSY"/QUASI-LINEAR STORM MODE AS OPPOSED TO SUSTAINED
DISCRETE SUPERCELLS...WHICH WOULD IN THEORY LIMIT THE TORNADO
THREAT BUT POTENTIALLY ENHANCE A MORE WIDESPREAD DAMAGING WIND
EVENT. LOCALLY HEAVY RAIN COULD BECOME AN ISSUE TOO...BUT DOUBT
MANY AREAS WOULD RECEIVE MORE THAN 2 INCHES GIVEN WHAT SHOULD BE
A FAIRLY PROGRESSIVE NATURE OF CONVECTION. IN THEORY...THE MAIN
SEVERE WEATHER THREAT IS WINDING DOWN BY MIDNIGHT OR SO...BUT
PLENTY OF ELEVATED CAPE COULD LINGER TO KEEP AT LEAST A HAIL
THREAT GOING LATER INTO THE NIGHT...ESPECIALLY WITHIN THE
NORTHEAST 1/2 OF THE CWA. TEMP-WISE...SIMPLY STUCK CLOSE TO A
MULTI-MODEL CONSENSUS WITH HIGHS MID-70S MOST AREAS AND SATURDAY
NIGHT LOWS MAINLY MID-UPPER 50S. APART FROM ANY THUNDERSTORM
ACTIVITY...IT WILL CERTAINLY BE A BREEZY/WINDY DAY AS WELL FROM
THE SOUTH-SOUTHEAST WITH SUSTAINED SPEEDS EASILY 20-25 MPH AND
GUSTS 30-35+ MPH AND LOCALLY HIGHER.

SUNDAY DAYTIME/NIGHT: THE CENTER OF THE MID LEVEL LOW IS PROGGED
TO BE OVER THE NEB/SD BORDER REGION AT SUNRISE...BEFORE LIFTING TO
AROUND THE MN/SD/ND BORDER BY SUNSET. AS THE TROUGH AXIS/COLD
FRONT CLEARS THE CWA...WINDS WILL REMAIN BREEZY BUT TURN
WESTERLY...WITH STRONGEST SPEEDS LIKELY NORTH OF I-80. WHILE MOST
OF THE CWA IS PROBABLY DRY...HAVE LINGERED SOME 20-40 POPS MAINLY
NEAR/NORTH OF THE I-80 CORRIDOR...ALONG WITH A LINGERING NON-
SEVERE STORM POSSIBILITY. GOOD LOW LEVEL MIXING COULD ACTUALLY
BOOST TEMPS WARMER THAN SATURDAY IN SOME AREAS...AND HAVE AIMED
FROM NEAR-70 FAR NORTHWEST TO NEAR-80 FAR SOUTHEAST. KEPT SUNDAY
NIGHT DRY BUT BREEZY AS HIGH PRESSURE STARTS BUILDING IN.

MONDAY DAYTIME/NIGHT: FAIRLY HIGH CONFIDENCE IN DRY WEATHER AS
SHORTWAVE RIDGING OVERSPREADS THE PLAINS. SEASONABLY COOL WITH
HIGHS IN 60S AND LOWS IN 40S...MAYBE EVEN 30S MAINLY FAR NORTH.

TUESDAY DAYTIME/NIGHT: THE NEXT MID-UPPER TROUGH SHIFTS INTO THE
PLAINS BUT SEEMS TO BE WEAKENING AS IT DOES SO. PROBABLY HIT POPS
TOO HARD DURING THE DAYTIME HOURS WHICH SHOULD MAINLY STAY
DRY...BUT TUESDAY NIGHT CURRENTLY APPEARS TO HOLD A DECENT CHANCE
OF RAIN. NORMALLY AM NOT COMFORTABLE WITH LIKELY (60+ PERCENT)
POPS THIS FAR OUT...BUT PREVIOUS FORECAST ALREADY HAD THEM SO WILL
KEEP THEM GOING. SEVERE STORM RISK LOOKS QUITE MINIMAL AT THIS
TIME.

WEDNESDAY DAYTIME/NIGHT: THE AFOREMENTIONED SYSTEM PULLS OUT OF
THE REGION...WITH BEST LINGERING RAIN CHANCES DURING THE DAY AND
NIGHT POPS POTENTIALLY KIND OF IFFY. PRELIMINARILY LOOKING LIKE
THE OVERALL COOLEST DAY OF THE WEEK.

THURSDAY DAYTIME: ALTHOUGH BY NO MEANS A GUARANTEE...COULD NO
LONGER JUSTIFY LOW PRECIP CHANCES FROM PREVIOUS FORECAST BASED ON
THE LATEST 00Z ECMWF/GFS SO REMOVED THEM. HIGH TEMPS AIMED MID
60S.

&&

.AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1223 PM CDT FRI MAY 15 2015

A SOMEWHAT DIFFICULT FORECAST FOR THE TERMINALS OVER THE NEXT 24
HOURS IS IN PLACE...WHICH IN TURN RESULTS IN LOWER CONFIDENCE
DURING THIS TIME AS WELL. THERE IS MUCH UNCERTAINTY REGARDING
SHOWERS/THUNDERSTORMS TIMING AND COVERAGE. THAT BEING SAID...THERE
ARE SOME SHOWERS/THUNDERSTORMS ACROSS NORTH CENTRAL KANSAS THAT
SHOULD SLOWLY MAKE THEIR WAY TOWARDS THE TERMINALS LATER THIS
AFTERNOON WHICH WILL RESULT IN STRONGER WIND SPEEDS AND LOWER
CEILINGS. MVFR CONDITIONS ARE FORECAST THROUGH MOST OF THE
TAF...BUT IFR CONDITIONS ARE NOT OUT OF THE QUESTION OVER THE NEXT
24 HOURS. IF THE SCATTERED SHOWERS/THUNDERSTORMS HOLD
TOGETHER...THEY COULD STICK AROUND FOR SEVERAL HOURS BEING MOSTLY
SCATTERED IN NATURE ACROSS THE AREA...AND BECAUSE THEY WILL BE
SCATTERED IN NATURE IT IS DIFFICULT PINPOINTING AN EXACT TIME FOR
ENTRANCE AND DEPARTURE FROM THE TERMINALS. OVERALL...AT LEAST
MVFR CONDITIONS SHOULD BE EXPECTED OVER A MAJORITY OF THE NEXT 24
HOURS WITH IFR CONDITIONS NOT OVERLY OUT OF THE QUESTION.

&&

.HYDROLOGY...
ISSUED AT 251 AM CDT FRI MAY 15 2015

FOR THOSE WHO MIGHT HAVE MISSED IT YESTERDAY...WE HAVE ISSUED A
FLOOD WARNING FOR THE PLATTE RIVER IN WESTERN DAWSON COUNTY
CURRENTLY VALID THROUGH 1045 AM SUNDAY...ALTHOUGH THIS MAY END UP
NEEDING EXTENDED IN TIME DEPENDING ON HOW THINGS PLAY OUT OVER THE
COMING DAYS. THIS MATCHES UP WITH WARNINGS FARTHER UPSTREAM INTO
LINCOLN COUNTY THAT NWS NORTH PLATTE HAS HAD OUT FOR A FEW DAYS
NOW. IN SHORT...THERE IS STILL CONSIDERABLE UNCERTAINTY REGARDING
HOW IMPACTFUL FLOODING WILL ACTUALLY BE IN WESTERN DAWSON
COUNTY...AND POSSIBLY DOWNSTREAM FROM THERE...BUT REAL-TIME GAUGE
DATA FROM THE BRADY/COZAD GAUGES SUGGEST THAT ESPECIALLY AREAS
UPSTREAM FROM COZAD WILL CONTINUE TO SEE A SLOW INCREASE IN MINOR
FLOODING ISSUES...INCLUDING THE KOA CAMPGROUND AREA NEAR
GOTHENBURG. PLEASE STAY UP TO DATE WITH THE LATEST FLOOD
WARNINGS/STATEMENTS OVER THE COMING DAYS...BUT PLEASE NOTE THIS
PLATTE RIVER FLOOD EVENT WITHIN OUR SOUTH CENTRAL NEBRASKA
COVERAGE AREA IS NOT EXPECTED TO BE AS NOTEWORTHY AS THE ONE
DURING FALL 2013.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&

$$

SHORT TERM...FAY
LONG TERM...PFANNKUCH
AVIATION...GUERRERO
HYDROLOGY...PFANNKUCH



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